Publications (22)
Towards a dynamical mass of the ultraluminous X-ray source NGC 5408 X-1
D. Cseh, F. Grise, P. Kaaret +5
We obtained multi-epoch Very Large Telescope (VLT) optical spectroscopic data in 2011 and 2012 on the ultraluminous X-ray source (ULX) NGC 5408 X-1. We confirm that the HeII\lambda…
Radio observations of NGC 6388: an upper limit on the mass of its central black hole
D. Cseh, P. Kaaret, S. Corbel +4
We present the results of deep radio observations with the Australia Telescope Compact Array (ATCA) of the globular cluster NGC 6388. We show that there is no radio source detected…
Into the central 10 pc of the most distant known radio quasar. VLBI imaging observations of J1429+5447 at z=6.21
S. Frey, Z. Paragi, L. I. Gurvits +2
Context: There are about 60 quasars known at redshifts z>5.7 to date. Only three of them are detected in the radio above 1 mJy flux density at 1.4 GHz frequency. Among them, J1429+…
Probing the Active Massive Black Hole Candidate in the Center of NGC 404 with VLBI
Z. Paragi, S. Frey, P. Kaaret +3
Recently Nyland et al. (2012) argued that the radio emission observed in the center of the dwarf galaxy NGC 404 originates in a low-luminosity active galactic nucleus (LLAGN) power…
Constraining the parameters of the putative supermassive binary black hole in PG 1302-102 from its radio structure
E. Kun, S. Frey, K. Ã. Gabányi +3
We investigate the pc-scale kinematics and kpc-scale radio morphology of the quasar PG 1302-102, which may harbour a sub-pc separation supermassive binary black hole system at its…
The evolution of a jet ejection of the ultraluminous X-ray source Holmberg II X-1
D. Cseh, J. C. A. Miller-Jones, P. G. Jonker +7
We present quasi-simultaneous, multi-epoch radio and X-ray measurements of Holmberg II X-1 using the European VLBI Network (EVN), the Karl G. Jansky Very Large Array (VLA), and the…
The accretion disc, jets and environment of the intermediate mass black hole candidate ESO 243-49 HLX-1
N. A. Webb, D. Barret, V. Braito +13
The Ultra Luminous X-ray (ULX) source HLX-1 in the galaxy ESO 243-49 has an observed maximum unabsorbed X-ray luminosity of 1.3e42 erg/s (0.2-10.0 keV). From the conservative assum…
The rise and fall of a binary AGN candidate: the story of PSO J334.2028+1.4075
P. Benke, S. Frey, K. Ã. Gabányi +7
Apparently periodic optical variations of the luminous high-redshift (z=2.06) quasar PSO J334.2028+1.4075 led Liu et al. (2015) to interpret the variability as the orbital period o…
Unveiling recurrent jets of the ULX Holmberg II X-1: evidence for a massive stellar-mass black hole?
D. Cseh, P. Kaaret, S. Corbel +10
We report on the discovery of an apparent triple radio structure hidden inside the radio bubble of the ultraluminous X-ray source Holmberg II X-1. The morphology is consistent with…
Constraining the radio jet proper motion of the high-redshift quasar J2134-0419 at z=4.3
K. Perger, S. Frey, K. Ã. Gabányi +12
To date, PMN J2134-0419 (at a redshift z=4.33) is the second most distant quasar known with a milliarcsecond-scale morphology permitting direct estimates of the jet proper motion.…
High-resolution images of five radio quasars at early cosmological epochs
S. Frey, Z. Paragi, L. I. Gurvits +2
Context: Until now, there have only been seven quasars at z>4.5 whose the high-resolution radio structure had been studied in detail with Very Long Baseline Interferometry (VLBI) i…
On the radio properties of the intermediate-mass black hole candidate ESO 243-49 HLX-1
D. Cseh, N. A. Webb, O. Godet +8
We present follow-up radio observations of ESO 243-49 HLX-1 from 2012 using the Australia Telescope Compact Array (ATCA) and the Karl G. Jansky Very Large Array (VLA). We report th…
A close look at compact triple radio sources
D. Cseh, A. Fuhl, S. Frey
We show an archival 1.4-GHz Very Large Array (VLA) image of the core-dominated triple (CDT) radio source J1628+3906, along with a recent high-resolution 5-GHz Very Long Baseline In…
Radiatively efficient accreting black holes in the hard state: the case study of H1743-322
M. Coriat, S. Corbel, L. Prat +7
In recent years, much effort has been devoted to unraveling the connection between the accretion flow and the jets in accreting compact objects. In the present work, we report new…
Broad Components in Optical Emission Lines from the Ultra-Luminous X-ray Source NGC 5408 X-1
D. Cseh, F. Grise, S. Corbel +1
High-resolution optical spectra of the ultraluminous X-ray source NGC 5408 X-1 show a broad component with a width of ~750 km/s in the HeII and Hbeta lines in addition to the narro…
Radio interferometric observations of two core-dominated triple radio sources at z>3
D. Cseh, S. Frey, Z. Paragi +2
Aims. We selected two radio quasars (J1036+1326 and J1353+5725) based on their 1.4-GHz radio structure, which is dominated by a bright central core and a pair of weaker and nearly…
Large-scale radio nebula around the Ultra-Luminous X-ray Source IC 342 X-1
D. Cseh, C. Lang, S. Corbel +2
We present discovery of a radio nebula associated with the ultraluminous X-ray source (ULX) IC 342 X-1 using the Very Large Array (VLA). Taking the surrounding nebula as a calorime…
VLBI observation of the newly discovered z=5.18 quasar SDSS J0131-0321
K. E. Gabanyi, D. Cseh, S. Frey +4
Few high-redshift, radio-loud quasars are known to date. The extremely luminous, radio-bright quasar, SDSS J013127.34-032100.1 was recently discovered at a redshift of . We…
Black Hole Powered Nebulae and a Case Study of the Ultraluminous X-ray Source IC342 X-1
D. Cseh, S. Corbel, P. Kaaret +6
We present new radio, optical, and X-ray observations of three Ultraluminous X-ray sources (ULXs) that are associated with large-scale nebulae. We report the discovery of a radio n…
The most distant radio quasars at the highest resolution
S. Frey, Z. Paragi, . L. I. Gurvits +2
There are about 50 quasars known at redshifts z>5.7 to date. Only three of them are detected in the radio (J0836+0054, z=5.77; J1427+3312, z=6.12; J1429+5447, z=6.21). The highest-…
The LOFAR Two-metre Sky Survey - I. Survey Description and Preliminary Data Release
T. W. Shimwell, H. J. A. Röttgering, P. N. Best +69
The LOFAR Two-metre Sky Survey (LoTSS) is a deep 120-168 MHz imaging survey that will eventually cover the entire Northern sky. Each of the 3170 pointings will be observed for 8 hr…
VLBI observations of four radio quasars at : blazars or not?
H. -M. Cao, S. Frey, K. Ã. Gabányi +5
Blazars are active galactic nuclei (AGN) whose relativistic jets point nearly to the line of sight. Their compact radio structure can be imaged with very long baseline interferomet…